The present invention relates to a resin molding product using an electrophotographic toner and a manufacturing method of the resin molding product particularly relates to a resin molding product that uses, as a molding compound of a core layer, the electrophotographic toner which cannot be used for an apparatus such as an image forming apparatus of an electrophotographic type so as to improve the quality of the resin molding product and a manufacturing method of the resin molding product.
According to a conventional art, in the manufacturing process of the electrophotographic toner, a fine toner is generated during the final classification step. Such a toner cannot be used as the product and does not fall within the standard particle diameter. The fine toner used to be discarded. However, a variety of suggestions have been made as to how to reclaim such a toner because of the recent concerns about the effective use of the raw material and environmental issues. According to one method of reclamation, for example, the fine toner is recycled during the manufacturing of the electrophotographic toner. As conventional examples dealing with the toner recycle, (a) a manufacturing method of an electrophotographic toner is disclosed in Japanese unexamined patent publication No.6-266157 (publication date: Sep. 22, 1994), and (b) a manufacturing method of a toner for developing the electrostatic charge is disclosed in Japanese unexamined patent publication No.8-69126 (publication date: Mar. 12, 1996). According to the manufacturing method disclosed in Japanese unexamined patent publication No.6-266157, the fine toner is made into pellet particles that can pass through a 2 mm mesh by a compression and granulating apparatus, and then is recycled in the toner manufacturing step. In the mean time, according to the manufacturing method disclosed in Japanese unexamined patent publication No. 8-69126, the fine toner is mixed, kneaded, and injected, and then is ground so as to form pellet particles. Thereafter, the pellet particles are recycled in the toner manufacturing step.
When using the image forming apparatus, the cleaning process generates a discard toner, which is a toner to be discarded. Image forming apparatus, having a mechanism for the toner recycle in which the discard toner is reclaimed, have been well know as the art.
Further, according to international unexamined patent publication No. WO97/38838 (international publication date: Oct. 23, 1997), disclosed is a method, for reclaiming a painted molding product, in which the discard toner is used. More specifically, in the method, a molding product that is constituted by a thermoplastic resin is painted by a paint made of a thermoplastic resin. The painted molding product is ground so as to obtain grounded pieces. The grounded pieces thus obtained are subjected to the molding so as to form another molding product. The molding product is then painted with the thermoplastic resin paint. Thus, the painted molding product is reclaimed. According to the reclamation method, the discard toner is added to the ground particles in a constant rate, or a constant amount of the toners to be discarded is added to the paint aspigment.
In the field of the molding technology of a plastic material, a combined structure known as the sandwiched structure is well known. The resin molding product having the sandwiched structure (hereinbelow referred to as the sandwiched molding product) is provided with a core layer as a main layer, and the core layer is coated with skin layers (outer layers).
Since the core layer is coated with the skin layers, the sandwiched molding product has the advantage that it is possible to make use of the properties of the respective materials to be selected as the respective layers. More specifically, for example, when using a material, such as a styrene-type resin, whose impact resistance is not adequate as the core layer, by coating the core layer with the skin layers that are made of a material having an excellent strength, preferably having the strength and stiffness of greater than the core layer, the core layer is strengthened and the appearance is improved.
The conventional arts of the sandwiched molding product, for example, are disclosed in the publications such as Japanese unexamined patent publication No. 2-251446 (publication date: Oct. 9, 1990) or Japanese unexamined patent publication No. 6-305081 (publication date: Nov. 1, 1994). The conventional arts are for improving the quality of the sandwiched molding product.
According to typical sandwiched molding products, the material of the core layer is different from that of the skin layer, and, as a result, the adhesive strength of each layer is not adequate. Accordingly, the integrality of the layers as the molding product is not adequate. According to the publication No. 2-251446, in order to solve this problem, a composite mainly made of poly phenylene-ether and poly-amid is used as the skin layer and a styrene-type resin is used as the core layer.
In the cooling process of the molding, the degree of shrinkage in each melting resin that becomes the molding compound of the core layer and the skin layer is sometimes different from each other. This causes the surface of the skin layer to have a hollow that is called a xe2x80x9chikexe2x80x9d, which is likely to damage the quality of the appearance in the molding product. According to the publication No. 6-305081, in order to solve this problem, an olefin thermoplastic elastomer or a styrene thermoplastic elastomer is used as the skin layer, and a mixture of a crystallizing polypropylene resin, and an ethylene-xcex1-olefin copolymer or a styrene elastomer is used as the core layer, and the skin layer contains a predetermined amount of fillers.
In view of the conventional art relating to toner recycle, no effective reclamation method has been established with regard to the fine toner, as well as to the discard toner. Rather, most of the fine toner and discard toner is, permanently disposed of without any recycle. This is a problem.
As to the reclamation of the fine toner, according to the respective publications No. 6-266157 and No. 8-69126, the fine toner generated in the manufacturing process is added again in the manufacturing process of the toner. The reclamation of the fine toner is thus carried out. This causes that the quality of the toner that is the final product to deteriorate when the amount of the fine toner is too much. Accordingly, the amount of the fine toner that can be practically reclaimed is limited.
More specifically, in order to maintain the quality of the printed image to be a level of not less than a predetermined level, the rate of the fine toner to be added in the toner manufacturing process is at most around 10 percent with respect to the entire toner amount. When the fine toner is generated at more than this rate, it cannot be avoided that the fine toner is discarded. Such discarded toner is used as fuel.
In the recycle of the discard toner that has been generated in the image forming apparatus, the similar problem arises. More specifically, according to the image forming apparatus having the toner recycle mechanism, when the rate of the discard toner becomes high in the electrophotographic toner, it is most likely that the image to be formed deteriorates. Accordingly, the discard toner contributes to the recycle only at a predetermined rate. Furthermore, when the discard toner is generated at a rate of more than the predetermined rate, it is not possible to process the discard toner as fuel, thereby resulting in that the discard toner is processed as dirt.
According to the art disclosed in the international unexamined patent publication No. WO97/38838, the discard toner is reclaimed in the painted. molding product. The rate of the amount of the discard toner that is used in the painted molding product is low, so that the painted molding product is inadequately formed. This does not allow (a) large amount of discard toner to be used and (b) improvement in the quality of the molding product that is subjected to recycle with use of the discard toner. Accordingly, it is hard to say that such an art makes good use of the discard toner.
In the mean time, according to the technical field of the foregoing sandwiched molding product, it has been true that the core layer should be provided at a low cost and high quality, and the molding work should be made with more ease.
More specifically, since the core layer is coated with the skin layers, its appearance can be ignored when an opaque material is used as the skin layer. In view of this fact, it has been well known that the wastes of the resin are used as the core layer. This allows effective reclamation of the wastes and reduces the cost of the sandwiched molding product.
However, the wastes of the resin are not uniform in their shapes and their compositions, and the wastes of the resin tend to deteriorate. This causes the possible problem that the quality of the sandwiched molding product deteriorates when the wastes are used as the core layer. For example, as described above, in the sandwiched molding product, important factors are the adhesive strength between the skin layer and the core layer and the degree of shrinkage of each layer. Therefore, it is preferable that the physical property of the molding compound constituting each layer are stable. This possibly causes the dimension stability of the core layer to become lowered and the strength of the core layer to become lowered, when the wastes are practically used as the molding compound of the core layer.
According to the art disclosed in the respective publications No. 2-251446 and No. 6-305081, it is intended to improve the quality of the sandwiched molding product that is obtained by appropriately selecting the resin compound that is used as the core layer and the skin layer and adding auxiliaries (subsidiary materials) such as fillers. However, the respective arts do not effectively use the feature that the wastes can be used as the molding compound of the core layer in the manufacturing of the sandwiched molding product. Even if the wastes of the resin are actually used, it is difficult to manufacture a molding product with high quality.
In view of the foregoing problems, the present invention is made, and its object is to provide a resin molding product and its manufacturing method with a low cost and high quality. In particular, an electrophotographic toner used as a molding compound may be (a) a nonstandard toner that is generated in the manufacturing process, and cannot be used as a commercial product, and (b) a discard toner that is a resultant of having been used once in an image forming apparatus of an electrophotographic type.
The inventors of the present invention earnestly consider the foregoing problems and originally found, so as to make the present invention, that (a) in the resin molding product in which a pellet molding compound is often used, the electrophotographic toner of the fine powder can be practically used as a main raw material of the core layer and (b) a sandwiched molding product having an excellent property can be easily obtained by using the electrophotographic toner as the main material of the core layer.
More specifically, the resin molding product of the present invention is composed of a core layer that contains the electrophotographic toner constituted by at least a binder resin and a coloring agent and skin layers with which the core layer is coated.
With this arrangement, the binder resin and the coloring agent are mixed so that the electrophotographic toner has the mechanical strength for image forming processes such as a development and a cleaning. This provides the core layer with enough strength in the sandwiched structure that forms the resin molding product.
Since the electrophotographic toner has a small diameter, it is possible to improve the impact resistance of the core layer. Further, since the electrophotographic toner has a low melting point, it is possible to carry out the molding work with ease. It is possible to effectively reclaim the electrophotographic toner especially when using the electrophotographic toner for the core layer that has previously been unable to be used.
It is preferable in the resin molding product that the electrophotographic toner is a nonstandard toner that cannot be used as toner products that are manufactured from raw materials containing binder resins and coloring agents.
With this arrangement, the electrophotographic toner used as the core layer is the nonstandard fine toner that is obtained in the manufacturing process of the electrophotographic toner and has a particle diameter of less than a predetermined diameter. This allows not only use of fine toner that does not fall within the required particle diameter of the product standard and that does not fall within the required toner physical property of not burning up, but also improves the quality of the sandwiched molding product. Thus, such a fine toner is effectively made use of
In the resin molding product, the electrophotographic toner is a discard toner that is a resultant of having been used once in an image forming apparatus of an electrdphotographic type.
With this arrangement, since the material of the electrophotographic toner used as the core layer is the discard toner, it is possible (a) to reclaim the discard toner rather than processing it as dirt and (b) to improve the quality of the sandwiched molding product so as to effectively make use of the discard toner.
It is preferable in the resin molding product that the electrophotographic toner further includes a carrier component.
With this arrangement, since the material of the electrophotographic toner contains a carrier component, it is possible not only to improve the strength of the core layer, but also to obtain a bulky molding product, while making good use of the carrier to be discharged during exchanging the development apparatus and other occasions.
It is preferable in the resin molding product that the carrier component is an iron-type carrier or a ferrite-type carrier.
With this arrangement, since the carrier component is an iron-type carrier or a ferrite-type carrier, it is possible that the sandwiched molding product has the shield effect.
Especially, iron-type carriers such as magnetite show a high shield effect at a direct current or a low frequency while ferrite-type carriers have a high resistance and show a high shield effect at a high frequency.
It is preferable in the resin molding product that the carrier component is contained in the electrophotographic toner within a range of 3 weight part to 10 weight part.
With this arrangement, since the carrier component is contained in the electrophotographic toner within a range of 3 weight part to 10 weight part, it is possible to ensure the handling property of the material of the core layer even in the core layer of the sandwiched molding product without any granulation. If it is not necessary to granulate the material of the core layer, it is possible to prevent damage to the resin of the core layer and it is also possible to avoid a complex manufacturing process because the granulation process can be omitted.
It is preferable in the resin molding product that the core layer further includes an additive.
With this arrangement, since the electrophotographic toner has a small particle diameter, the electrophotographic toner and the additive are mixed and kneaded so that the additive is effectively dispersed over the entire core layer. This additive improves the performance of the sandwiched molding product.
It is preferable in the resin molding product that the additive is a fire retardant.
With this arrangement, by mixing and kneading the electrophotographic toner and the fire retardant, the fire retardant is effectively dispersed over the entire core layer. This improves the fire retardant performance of the sandwiched molding product.
It is preferable in the resin molding product that the fire retardant does not contain a halogen element.
With this arrangement, since the fire retardant does not contain a halogen element, it is possible to, avoid environmental pollution due to the fire retardant, and it is also possible to recycle the sandwiched molding product thus manufactured.
It is preferable in the resin molding product that the binder resin constituting the electrophotographic toner in the core layer is a styrene-type resin.
With this arrangement, since the styrene-type resin, which has an excellent toner performance as the binder resin, is used as the material of the electrophotographic toner, it is possible to improve the injection molding workability of the core layer.
It is preferable in the resin molding product that the skin layer includes a resin of a type similar to the binder resin constituting the electrophotographic toner in the core layer. With this arrangement, since the skin layer includes a resin similar to the principal component of the electrophotographic toner, the resins are compatible and, thus, the core layer and the skin layer are molten and mixed in a boundary surface so as to form a strong laminate surface. Since the thermal expansions of similar resins are substantially equal to each other, it is possible to prevent exfoliation and thermal denaturation caused by thermal stress in the boundary surface due to differences in thermal expansions. Further, since the core layer and the skin layer are made of styrene-type resins, it is possible to improve the workability of the sandwiched molding product and to improve the quality of the sandwiched molding product thus manufactured.
It is preferable in the resin molding product that the styrene-type resin is an ABS resin or a polystyrene resin. With this arrangement, since the styrene-type resin, forming the skin layer is an ABS resin or a polystyrene resin, the core layer and the skin layer are made of a similar material. This suppresses the stress due to the linear expansion during molding and allows the recycle to be carried out with ease. In particular, the ABS resin has strength and excellent injection molding workability. Further, the ABS resin has active co-molten property so as to provide strength in the boundary surface, and improves the fire retardancy of the resin molding product thus manufactured.
It is preferable in the resin molding product that the binder resin constituting the electrophotographic toner in the core layer is a polyester resin.
With this arrangement, since the electrophotographic toner uses a polyester resin as the binder resin, it is possible to reclaim as the core layer (a) the fine toner obtained especially in the manufacturing process of an electrophotographic toner in which the electrophotographic toner is used as a color toner or a negatively charged toner and (b) the discard toner that is obtained during image forming. Further, since the core layer and the skin layer are made of polyester resins, it is possible to improve the workability of the sandwiched molding product and it is also possible to improve the quality of the sandwiched molding product.
According to the present manufacturing method, a resin molding product is formed by coating a core layer material fabricated of an electrophotographic toner that is composed of a binder resin and a coloring agent with skin layer material fabricated of a resin.
According to this method, since the binder resin and the coloring agent are mixed to form an electrophotographic toner having mechanical strength for image forming processes such as a development and a cleaning, a strong core layer of the sandwiched molding product is provided. Since the electrophotographic toner has a small particle diameter, impact resistance of the core layer is improved, thereby improving the performance of the core layer itself. Further, since the electrophotographic toner has a low melting point, it is possible to carry out the molding work with ease. It is also possible to effectively reclaim the electrophotographic toner, especially the core layer that has previously not been usable.
It is preferable in the manufacturing method of the resin molding product that a sandwiched molding method is carried out so as to coat the core layer material with the skin layer material. The sandwiched molding method comprises the sequential steps of: (a) injecting molten skin layer material from a skin layer injecting unit toward a cavity section provided in a metal mold; (b) respectively injecting molten skin layer material from the skin layer injecting unit and molten core layer material from a core layer injecting unit; and (c) injecting again, with pressure, the molten skin layer material from the skin layer injecting unit.
According to this method, the core layer and the skin layer are formed by a single processing operation, thereby improving the workability of the sandwiched molding product.
It is preferable in the manufacturing method of the resin molding product that the electrophotographic toner is a nonstandard toner that is unusable as toner products that are manufactured in a manufacturing process from raw materials containing the binder resin and the coloring agent.
With this arrangement, the electrophotographic toner used as the core layer is a nonstandard fine toner that is obtained in the manufacturing process and has a particle diameter of less than a predetermined diameter. This allows not only use of the fine toner that does not falls within the required particle diameter of the product standard and that does not fall within the required toner physical property without burning up, but also improves the quality of the sandwiched molding product thus manufactured. Thus, such a fine toner is effectively made use of.
It is preferable in the manufacturing method of the resin molding product that the electrophotographic toner is a discard toner that is a resultant of carrying out a series of image forming processes.
According to this method, since the discard toner is used as the electrophotographic toner core layer material, it is possible to reclaim the discard toner without it being processed as dirt and it is possible to improve the quality of the sandwiched molding product so as to effectively make use of the discard toner.
It is preferable in the manufacturing method of the resin molding product that the electrophotographic toner further includes a carrier component.
In this manufacturing method, since the material of the electrophotographic toner contains a carrier component, it is possible not only to improve the strength of the core layer, but also to obtain a bulky molding product.
It is preferable in the manufacturing method of the resin molding product that the electrophotographic toner used as the core layer material is first subjected to a granulating step for forming particles having a predetermined size.
In this manufacturing method, since the electrophotographic toner used as the core layer material is first formed into particles having a predetermined size, the handling property of the core layer is accordingly ensured. Especially, in the case of the fine toner, great improvement in the handling property is achieved.
It is preferable in the manufacturing method of the resin molding product that the granulating step is carried out in a continuous extrusion apparatus for melting, mixing, and kneading, which is in accordance with the procedures in which the electrophotographic toner supplied from a raw material supply port is molten by a barrel, is sent to an outlet port by a screw, is injected outside via a die head of the outlet port, is cooled down, is solidified, and is cut so as to be formed into pellets for granulation.
According to this method, granulation of the electrophotographic toner is effectively carried out by a continuous extrusion apparatus for melting, mixing, and kneading. The dispersion of additives, which provide physical properties, and the granulation step can be concurrently carried out.
It is preferable in the manufacturing method of the resin molding product that an inner diameter D of the barrel and a length L between the raw material supply port and the outlet port satisfy L/Dxe2x89xa77.
According to this method, it is possible to increase the supply efficiency in the granulating step.
It is preferable in the manufacturing method of the resin molding product to use a twin-screw type extrusion apparatus.
According to this method, it is possible to avoid the instability of supply due to the entrainment of air that occurs when the extrusion apparatus has a single screw.
It is preferable in the manufacturing method of the resin molding product to use a strand type die head.
According to this method, it is possible to obtain the great granulating efficiency by suppressing the fine toner generated in the final grinding of the granulating process.
It is preferable in the manufacturing method of the resin molding product that the granulating step is carried out in the continuous extrusion apparatus for melting, mixing, and kneading which is in accordance with the procedures in which the electrophotographic toner supplied from a raw material supply port is molten, is injection-molded to have a long size so as to be subsequently ground, and the ground toner is classified by a sieve (a screen mesh). According to this method, it is possible to appropriately select a mesh scale division of the particles, thereby ensuring effective granulation.
It is preferable in the manufacturing method of the resin molding product that the scale division of the sieve falls within a range of 10 mm to 15 mm.
According to this method, it is possible to obtain greater granulating efficiency by suppressing the fine toner to be generated in the final grinding of the granulating process.
Further, it was found that in the case where the electrophotographic toner is used as the main raw material of the core layer of the sandwiched molding product, the core layer loses the elasticity and becomes fragile. In the resin molding product and its manufacturing method, it is very important to avoid the above phenomenon. Accordingly, the inventors of the present invention earnestly considered the foregoing problem and found a structure and method that avoids the above phenomenon. Thus, the present invention was made.
More specifically, the resin molding product in accordance with the present invention, in order to solve the above problem, is composed of (a) a core layer that contains at least an electrophotographic toner and an additive resin and (b) skin layers with which the core layer is coated. The additive resin is compatible with a binder resin that is used in the electrophotographic toner. Further, the core layer given elasticity, while the additive resin and the binder resin are co-molten.
With this arrangement, the binder resin that is used in the electrophotographic toner has mechanical properties that makes it endurable for development and cleaning in image forming processes. Further, the binder resin softens at a relatively low temperature so as to correspond to a fixing process via heat addition. Still a further, since the material of the electrophotographic toner as waste is uniform, the core layer becomes more stable. This provides a core layer that is fully stability because the resin hardly deteriorates even when reclaiming the electrophotographic toner as the molding compound of the core layer. In addition, the molding compound of the core layer is constituted by at least an electrophotographic toner and an additive resin, thereby providing elasticity to the core layer which is short of impact resistance so as to improve the problem of fragility. Accordingly, it is possible to obtain an excellent resin molding product having a sandwiched structure and having impact resistance and elasticity.
It is preferable in the resin molding product that the electrcphotographic toner that is contained in the molding compound is a styrene-type toner-whose binder resin is a styrene-type resin, and the additive resin is an aromatic vinyl-type copolymer having a rubber property. It is more preferable that the styrene-type resin is a styrene-acryl-type resin, and the aromatic vinyl-type copolymer having a rubber property is a graft copolymer of a styrene-type monomer and a rubber copolymer.
With this arrangement, since the styrene-type resin is used as the binder resin in the electrophotographic toner, and since it is used in a monochrome image forming apparatus, which is so often used, it is possible to effectively reclaim the electrophotographic toner when a styrene-type toner is used in the above molding compound.
In addition, the styrene-type resin, especially the styrene-acryl-type resin, has mechanical strength and a highly accurate dimension. Because of these advantages, it is possible to obtain a core layer having high quality. Further, the additive resin, is an aromatic vinyl-type copolymer having a rubber property, especially a graft copolymer of a styrene-type monomer and a rubber copolymer. Thus, the additive resin is fully compatible with the styrene-type resin, thereby providing elasticity to the core layer so as to further improve the quality of the core layer.
It is preferable in the resin molding product that the molding compound has a content of 50 weight part to 80 weight part electrophotographid toner.
With this arrangement, since the content of the electrophotographic toner material in the molding compound falls within the above range, it fully ensures the molding workability and ensures a fixed content of the additive resin. Thus, it is possible to obtain a strong core layer. Further, half or more than half of the core layer is electrophotographic toner that will be reclaimed. Thus, the present invention is an effective reclamation method of electrophotographic toner.
It is preferable in the resin molding product that the molding compound includes a carrier used for a two-component developer.
With this arrangement, since the molding compound includes a carrier, the strength of the core layer improves, and it is possible to obtain a bulky molding product. Further, since the core layer includes the carrier, it is possible to provide a shield effect with respect to the core layer.
It is preferable in the resin molding product that the core layer further includes a plasticizer.
With this arrangement, since the plasticizer further improves elasticity, the core layer becomes less fragile. The impact resistance also improves, accordingly.
It is preferable in the resin molding product that the skin layer includes an aromatic vinyl-type resin as a principal component.
With this arrangement, since the skin layer and the core layer include similar types of resins as their principal components, the respective layers are molten and mixed in a boundary surface so as to form a strong laminate surface. Since the thermal expansions are substantially equal to each other over the resin molding product, it is possible to prevent exfoliation and thermal denaturation caused by thermal stress in the boundary surface due to differences between the thermal expansions.
A manufacturing method of a resin molding product in accordance with the present invention, in order to solve the foregoing problem, comprises the steps of: (a) preparing a molding compound that is used as a core layer, the molding compound including an electrophotographic toner whose binder resin is a styrene-type resin and an additive resin that has a compatibility with the binder resin and gives an elasticity to the core layer while the additive resin and the binder resin are co-molten; and (b) coating the core layer with the skin layers.
According to this method, the binder resin used in the electrophotographic toner has an excellent mechanical property and the, material of the electrophotographic toner as waste is uniform. Accordingly, when using the electrophotographic toner as the molding compound of the core layer, it is possible to manufacture a resin molding product having excellent physical properties.
Since the melting point of the electrophotographic toner is set relatively low so that it is molten in a fixing process of the image forming step, the electrophotographic toner is excellent in molding workability even when it is reclaimed as a resin molding product. Further, since the electrophotographic toner has a small particle diameter, it is possible to very easily mix it to a degree such that a variety of auxiliaries that are added during molding become uniform. For this reason, a resin molding product having excellent properties is obtained by reclaiming the electrophotographic toner for the molding compound of the core layer.
It is preferable in the manufacturing method of the resin molding product that either a nonstandard toner that is obtained during the manufacturing process or a discard toner that is generated after it was used as a developer is used as the electrophotographic toner.
According to this method, it is possible in to effectively reclaim the nonstandard toner or the discard toner that were subjected to permanent disposal in the past. Furthermore, it is possible to summarize and recover the respective toners with relative ease without any impurities that affect the molding work and reduce the quality of the resin molding product. Thus, the respective toners are low cost and have excellent quality as the molding compound of the core layer. Therefore, it is possible to manufacture a sandwiched molding product having higher quality with low cost.
It is preferable in the manufacturing method of the resin molding product that the molding compound further includes auxiliaries that provide various properties to the resin molding product. The additive resin and the auxiliaries are added to the electrophotographic toner, and are stirred and mixed. According to this method, although it is no t easy in general to uniformly disperse materials such as auxiliaries to a molding compound, since the principal component of the molding compound is a fin e particle or fine toner, it is possible to easily prepare the molding compound by merely adding the additive resin and the auxiliaries to the electrophotographic toner, and stirring and mixing them. Especially, when using a particle additive resin such as a pellet, it is possible to uniformly disperse the auxiliaries to the resin material (the electrophotographic toner) merely by stirring and mixing, because the auxiliaries generally have a shape that is easy to be dispersed.